4 Preliminary Results 
Only a few preliminary results can be presented here. Fig. 1 shows a 512 x 512 section of 
a test image (X-Band, VV polarization, from the AGRISAR campaign). The 4 white-lined 
Figure 1: SAR test image 
windows in the upper part of the test image are named fieldl through fieldj, from left to 
right respectively, whereas the 3 windows in the lower part of the image are called field5 
through field7, from left to right respectively. Table I shows results for fieldj of 80 x 80 
pixels size (upper right window in Fig. I): discarding of prominent events rendered 222 peaks 
and 241 valleys for that field. Size and dynamic range were measured for these extrema. 
The table shows, as a twodimensional histogram, the respective number of peaks (upper left 
entry in each histogram element) and number of valleys (lower right entry) for the different 
combinat ions of size (given as radius measured at the basis of the extreme in the resampled 
window where the enlargement factor is 8) and dynamic range. We find that the extrema of 
fieldboth peaks and valleys, are clustering at values of 10 - 14 subpixels for the radius and 
30 - 50 graylevels for the dynamic range. 
In contrast, Table 2 shows results for field7 of 83 x 78 pixels size (lower right box in Fig. 1): 
form parameters for 235 peaks and 253 valleys were measured after discarding prominent 
events. The format of the table is identical to that of Fable 1. We find that the extrema of 
field7, both peaks and valleys, cluster at values of 13 - 16 subpixels for the radius and 80 - 120 
graylevels for the dynamic range. 
Results for other testficlds are similar. To check the consistency of these measurements, we 
evaluated correlation coefficients bet ween t he histograms of the different fields, separately for 
peaks and valleys. Fable 3 shows the result. Upper entries stand for the coefficients of the 
peak parameter histograms while lower entries show the coefficients of the valley parameter 
histograms. It is obvious that the form parameters of the first 4 fields (visually identified as 
being similar) as well as t hose of the last 3 fields (being similar to each other) correlate quite 
well, while the correlation of the parameters bet ween differing fields is very low. 
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